Combined telegraph and telephone system



2 Sheets-Sheet 1.

(No Model.)

(LA. SHEA. COMBINED TELEGRAPH AND TELEPHONE SYSTEM.

Patented Mar. 5, 1895.

XTNEEEIEE fined 2 Sheets-Sheet 2.

(No Model.) I

O. A. SHEA. COMBINED TELEGRAPH AND TELEPHONE SYSTEM.

No. 535,299. Patented Mar. 5, 1895.

CHRISTOPHER A. SHEA, OF BOSTON, MASSACHUSETTS.

COMBINED TELEGRAPH AND TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 535,299, dated March 5, 1895.

Application filed January 3, 1 393. Serial No. 457,066. (No model.)

To all whom it may concern.-

Be it known that I, CHRISTOPHER A. SHEA, a citizen of the United States, residing at Boston,in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in a Combined Telegraph and Telephone System, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification, in explaining its nature, in which- Figure l is a diagram view illustrating the improved system. Figs. 2 and 3 illustrate modifications to which reference will hereinafter be made.

Line 1 and line 2 comprise the two sides of a telephone metallic circuit.

0 is a telephone converter. It will be desirable to use those having the highest efficiency, and converters are now in use which have an efficiency of ninety per cent.

R, R, lit and R are inductive resistances.

K is a condenser to complete the telephone circuit.

B B are branches in which the telegraph instruments Tare placed. Between the branch 13 and the main line is provided a loop, in the branches of which are interposed the inductive resistances R R and the branches of this loop are coiled around the converter in opposite directions, and then connected with the mainline 1. Thus the converter will be oppositely vibrated by concurrent impulses traveling along the branches of the loop either from the telegraph instrument or from the main line. A similar arrangement is provided with line 2. Any current arriving from branch B divides and flows via R and R, and by coils c and c, differentially and equally around the core of the converter and to line. The telephone T will not be dis turbed by such current, there being no action in the converter arising from it. All currents from branch B also flow equally and differentially around the core of the converter 0, ma R and R coils c and c to line, the telephone being inoperative to these signals.

The incoming telegraph currents of any potential whatever will not be felt in the telephone, as these too divide and flow equally and differentially around the converter. The

telephone currents take the serialpath of line 1, coil 0 condenser K, coilcand line 2. Thus the condenser K, coil 0, and line 2 form a return circuit for incoming telephonicimpulses arriving along the branch 0 of the loop in line 1, While the condenser K, coil 0 and line 1 form a return circuit for incoming telephonic impulses arriving along the branch e of the loop of the oppositeline. These currents will nottraverse coils c and 0 the inductance of R and R making an impassable barrier; neither will they go via. R and R on account of the inductance.

The fact that any telegraphic current strength can be used enables a quadruplex or multiplex telegraph apparatus of any kind to be put on branch B or B or both, thereby increasing the capacity of every circuit a number of times over the present system. Notwithstanding this great increase in the service of each line, both the telegraph and telephone systems will Work better than the one now in use, for the reason that the telegraphic circuit is not loaded down with retardation and resistances and the telephone, being in a perfect balance, will not reproduce the telegraphic signals.

The converter 0 will be inoperative to all the telegraphic currents, but the telephone currents traversing the circuit of line 1, coil 0 converter K, coil 0, and line 2 will be reproduced in the telephone with only a slight pen centage of loss.

When the transmitter T R is spoken into, the speech will be produced in the circuit just named and will operate the distant telephone.

In this invention, it will be noticed, the feature of graduating, so called, is absent; and the effect of all telegraph currents in the tele phones is neutralized by causing them to separate and flow in opposite directions about the telephone converter. This permits each line to be brought up to its full capacity, that is, the telephone service is continuous and effective,while the telegraph service is increased from a single service on each line of the metallic circuit to a quadruplex or any multiplex system without hurting the telephone service.

It will be understood that the capacity of each line or Wire now is limited to single Wire telegraph service and will not stand forty' cells of battery without causing pulsation in the telephone, and the quad ruplex, which employs about three hundred and eighty cells, cannot possibly be used with the present system.

Another advantage arising from this system is that the incoming telegraph currents are also neutralized so far as their effect upon the telephone is concerned.

Another advantage is that the telegraph current is retarded only to a very small extent, as it meets only the joint resistance of the two coils R R, c c, which reduce the resistance to that of one-half of one coil.

I have shown thetelephone T wound on the middle of the converter merely for clearness. By the system shown in Fig. 1 cross-writing will occur by the discharge of the condenser K. This can be obviated by the arrangement shown in Fig. 2, where two condensers instead of one are placed between R and R, and a ground established between the two. This ground will assist the telephone current and give it better quality, for when it arrives at K or K, it will take the return route of smallest resistance, the earth, instead of traversing the other wire, where it would meet considerable retardation.

The ground between the condensers K K will not make the telephone noisy, as it is connected in the middle and to coils c c in opposite directions. The retardation to the telegraph current in circuit R 0 due to the condenser can be balanced by an equal retardation in R c, and the same is of course true of the divided branches R R This is shown in Fig. 2 where A is an inductive resistance coil; B ,non-inductive resistance, which balances A when the condensers discharge, preventing a pulsation in the telephone. 0' and D perform the same functions.

I will here mention that two converters instead of one may be used-that is, the line wires connected to two separate converters, and the telephone connected to both, in the well known way; but I prefer using one converter, one reason being to have the loss of the telephone currents as small as possible.

In Fig. 3, R and R are inductive resistances. R and R are non-inductive resistances. The resistance in R is just sufficient to balance the flow of telegraph current in R which allows equal amounts to flow around the converter differentially. The same is true of R and R. The route of the telephone current is line 1, coil 0 non-inductive resistance R, condensers K, K, R 0 and line 2, reproducing in the telephone. They will not shunt via 0' or c on account of inductance at R and R duce the telephone currents to any appreciable extent.

Having thus fully described my invention, I claim and desire to secure by Letters Patent of the United States 1. In a telegraph and telephone system two The resistances in R and R will not retelegraph lines, an interposed converter around which both lines are coiled, and one or more condensers between said lines, to complete the telephone circuit, and between the converter and telegraph instrument or instruments.

2. In a combined telegraph and telephone system, the combination, with a main line, and a telegraph instrument, of a loop between the telegraph instrument and the main line,

a telephone oppositely vibrated by concurrent impulses along the two branches of the loop, a barrier in one of said branches for incoming telephonic impulses, and a return circuit for such impulses arriving along the other branch, substantially as described.

3. In a combined telegraph and telephone system, the combination, with a main line, of a telegraph instrument, a loop between the telegraph instrument and the main line, a telephone oppositely vibrated by concurrent impulses along the two branches of the loop, a return circuit for incoming telephonic impulses connected with one of said branches, and a barrier for said impulses through the other branch, substantially as described.

4. In a combined telegraph and telephone system, the combination, with a main line, of a telegraph instrument, a loop between the telegraph instrument and the main line, a telephone converter about which the two branches of the loop are wound in opposite directions, a return circuit for incoming tele phonic impulses connected with one of said branches and a barrier for said impulses through the other branch, substantially as described.

5. In a combined telegraph and telephone system, the combination of two main lines, independent telegraph instruments therefor, loops between the instruments and the main lines, a telephone oppositely vibrated by concurrent impulses along the branches of either loop, a barrier for incoming telephonic impulses in one branch of either loop, and a return circuit or circuits for such impulses along the other branches, substantially as described.

6. In a combined telegraph and telephone system, the combination, with a main line and a telegraph instrument, of a loop interposed between said line and instrument, a telephone oppositely vibrated by concurrent impulses along the two branches of the loop, an induce ive resistance in one of said branches, a noninductive resistance in the otherbranch, and a return telephonic circuit, substantially as described.

7. In a combined telegraph and telephone system, the combination of a main line, two incoming branches proceeding therefrom,a telephone oppositely vibrated by concurrent impulses along the two branches, each branch being connected with the home telegraph in strument and also with earth through a condenser, an inductive resistance opposing telephonic impulses along one of said branches to the condenser, and a balancing non-inductive resistance in the circuit of the telephonic impulses along the other branch, substantially as described.

8. In a combined telegraph and telephone system, the combination of telegraph and telephone instruments, a main line coiled about the telephone or converter core, a branch wire from the telegraph instrument oppositely coiled about said core, means for stopping telephonic impulses along said branch wire, and a return telephonic circuit, substantially as described.

9. In a combined telegraph and telephone system, the combination of two main lines, independent telegraph instruments therefor, a telephone or telephone converter, two branches proceeding from each telegraph instrumentand oppositely wound about the telephone or converter core, one of said branches at each side being connected with its main CHRISTOPHER A. SHEA.

Witnesses:

F. F. RAYMOND, 2d, J. M. DOLAN. 

